Scientists have discovered that a detectible increase in the blood content of superficial mucous membrane occurs proximate cancerous and precancerous lesions in the colon relative to the blood content of healthy tissue as described in, for example, R. K. Wali, H. K. Roy, Y. L. Kim, Y. Liu, J. L. Koetsier, D. P. Kunte, M. J. Goldberg, V. Turzhitsky, and V. Backman, Increased Microvascular Blood Content is an Early Event in Colon Carcinogenesis, Gut Vol. 54, 654-660 (2005), which is incorporated by reference herein. This phenomenon is referred to as early increase in blood supply (EIBS).
Currently, there are no known capsule devices for detecting blood content in the colon or other lumens of an organism. There are capsule endoscopes that provide images of the inside of a gastrointestinal tract or other regions along the digestive tract. These capsule endoscopes are small enough to be swallowed by a person or animal. They generally includes an image capture device such as a CCD device. Capsule endoscopes enable alternative diagnostic and screening procedures relative to conventional endoscopes for detecting diseases in the digestive tract such as gastroesophagus reflux and gastric ulcers. Such procedures are less invasive than conventional endoscopes which use a long, thin tube inserted through the esophagus, small intestine, colon, and rectum. Known capsule endoscopes capture images but do not provide blood content information of tissue along the digestive tract.
It is desirable to have a non-invasive device or method for detecting the blood content of the tissue along the digestive tract for screening or diagnosis of particular diseases and for other purposes.